Elder son doesn't have a share in the will.

We are four brothers and three sisters and I am the oldest son. my father brought a land in prime area of Agartala,Tripura in my mothers name. father died long ago and my mother died on january 2010. my mother first made a will equally among four brothers.after that she changed the will and given the total property equally to the youngest brother and wife of third brother. i didn't know anything about both the cases taking the advantages of my faith in them and love and also i lived my life out of Tripura. my age is above seventy yrs. and having no pension.due to my age, poverty, and distance from kolkata (now i live in kolkata) i am helpless and in sufferings.i think they have not taken the probate of the will. considering the above is there any way of getting legal help?